Fixes for PointType; added distanceFrom(otherPoint)

bundles/core/org.openhab.core.library.test/src/test/java/org/openhab/core/library/types/LocationItemTest.java

@@ -34,10 +34,10 @@ public void testDistance() {
 		LocationItem locationBerlin = new LocationItem("berlin");
 		locationBerlin.setState(pointBerlin);
 
-		DecimalType distance = locationParis.distanceFrom(pointParis);
+		DecimalType distance = locationParis.distanceFrom(locationParis);
 		assertEquals(distance.intValue(),0);
 
-		double parisBerlin = locationParis.distanceFrom(pointBerlin).doubleValue();
+		double parisBerlin = locationParis.distanceFrom(locationBerlin).doubleValue();
 		assertEquals(parisBerlin,878400,50);	
 
 		double gravParis = pointParis.getGravity().doubleValue();

bundles/core/org.openhab.core.library/src/main/java/org/openhab/core/library/items/LocationItem.java

@@ -48,27 +48,16 @@ public List<Class<? extends Command>> getAcceptedCommandTypes() {
 	}
 
 	/**
-	 * Compute the distance with another Point type,
-	 * http://stackoverflow.com/questions/837872/calculate-distance-in-meters-when-you-know-longitude-and-latitude-in-java
+	 * Return the distance from another LocationItem.
 	 * @return distance between the two points in meters
 	 */
-	public DecimalType distanceFrom(PointType away){
-
-		double dist = -1;
-
-		if ((away != null) && (this.state instanceof PointType)) {
-
-			PointType me = (PointType) this.state;
-
-			double dLat = Math.pow(Math.sin(Math.toRadians(away.getLatitude().doubleValue() - me.getLatitude().doubleValue()) / 2),2);
-			double dLng = Math.pow(Math.sin(Math.toRadians(away.getLongitude().doubleValue() - me.getLongitude().doubleValue()) / 2),2);
-			double a = dLat + Math.cos(Math.toRadians(me.getLatitude().doubleValue()))  
-							* Math.cos(Math.toRadians(away.getLatitude().doubleValue())) * dLng;
-
-			dist = PointType.WGS84_a * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
+	public DecimalType distanceFrom(LocationItem awayItem) {
+		if (awayItem != null && awayItem.state instanceof PointType && this.state instanceof PointType) {
+			PointType thisPoint = (PointType)this.state;
+			PointType awayPoint = (PointType)awayItem.state;
+			return thisPoint.distanceFrom(awayPoint);
 		}
-
-		return new DecimalType(dist);
+		return new DecimalType(-1);
 	}
 
 }

bundles/core/org.openhab.core.library/src/main/java/org/openhab/core/library/types/PointType.java

@@ -13,6 +13,7 @@
 import java.util.SortedMap;
 import java.util.TreeMap;
 
+import org.apache.commons.lang.StringUtils;
 import org.openhab.core.types.Command;
 import org.openhab.core.types.ComplexType;
 import org.openhab.core.types.PrimitiveType;
@@ -74,15 +75,18 @@ public PointType(StringType latitude, StringType longitude,
 	}
 
 	public PointType(String value) {
-		if (!value.isEmpty()) {
+		if (StringUtils.isNotBlank(value)) {
 			String[] elements = value.split(",");
 			if (elements.length >= 2) {
-				canonicalize(new DecimalType(elements[0]), new DecimalType(
-						elements[1]));
+				canonicalize(new DecimalType(elements[0]), new DecimalType(elements[1]));
 				if (elements.length == 3) {
 					setAltitude(new DecimalType(elements[2]));
 				}
+			} else {
+				throw new IllegalArgumentException(value + " is not a valid PointType syntax");
 			}
+		} else {
+			throw new IllegalArgumentException("Constructor argument must not be blank");
 		}
 	}
 
@@ -112,6 +116,25 @@ public DecimalType getGravity() {
 		return new DecimalType(result);
 	}
 
+	/**
+	 * Return the distance in meters from otherPoint, ignoring altitude. This algorithm also
+	 * ignores the oblate spheroid shape of Earth and assumes a perfect sphere, so results
+	 * are inexact.
+	 *
+	 * @param otherPoint
+	 * @return distance in meters
+	 * @see <a href="https://en.wikipedia.org/wiki/Haversine_formula">Haversine formula</a>
+	 */
+	public DecimalType distanceFrom(PointType otherPoint) {
+		double dLat  = Math.toRadians(otherPoint.latitude.doubleValue() - this.latitude.doubleValue());
+		double dLong = Math.toRadians(otherPoint.longitude.doubleValue() - this.longitude.doubleValue());
+		double a = Math.pow(Math.sin(dLat / 2D), 2D) + Math.cos(Math.toRadians(this.latitude.doubleValue()))
+				* Math.cos(Math.toRadians(otherPoint.latitude.doubleValue()))
+				* Math.pow(Math.sin(dLong / 2D), 2D);
+		double c = 2D * Math.atan2(Math.sqrt(a), Math.sqrt(1D - a));
+		return new DecimalType(WGS84_a * c);
+	}
+
 	/**
 	 * <p>
 	 * Formats the value of this type according to a pattern (@see
@@ -129,13 +152,20 @@ public String format(String pattern) {
 		return String.format(pattern, getConstituents().values().toArray());
 	}
 
-	public PointType valueOf(String value) {
+	public static PointType valueOf(String value) {
 		return new PointType(value);
 	}
 
 	@Override
 	public String toString() {
-		return String.format("%1$.2f°N, %2$.2f°W, %3$.2f m", latitude, longitude, altitude);
+		StringBuilder sb = new StringBuilder(latitude.toPlainString());
+		sb.append(',');
+		sb.append(longitude.toPlainString());
+		if (!altitude.equals(BigDecimal.ZERO)) {
+			sb.append(',');
+			sb.append(altitude.toPlainString());
+		}
+		return sb.toString();
 	}
 
 	@Override